cmplog runtime for LLVM

1 files changed, 422 insertions, 0 deletions

diff --git a/llvm_mode/afl-llvm-cmplog.rt.o.c b/llvm_mode/afl-llvm-cmplog.rt.o.c
new file mode 100644
index 00000000..ef944d4f
--- /dev/null
+++ b/llvm_mode/afl-llvm-cmplog.rt.o.c
@@ -0,0 +1,422 @@
+/*
+   american fuzzy lop++ - LLVM instrumentation bootstrap
+   ---------------------------------------------------
+
+   Written by Laszlo Szekeres <lszekeres@google.com> and
+              Michal Zalewski
+
+   LLVM integration design comes from Laszlo Szekeres.
+
+   Copyright 2015, 2016 Google Inc. All rights reserved.
+   Copyright 2019-2020 AFLplusplus Project. All rights reserved.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at:
+
+     http://www.apache.org/licenses/LICENSE-2.0
+
+   This code is the rewrite of afl-as.h's main_payload.
+
+*/
+
+#ifdef __ANDROID__
+#include "android-ashmem.h"
+#endif
+#include "config.h"
+#include "types.h"
+#include "cmplog.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <unistd.h>
+#include <string.h>
+#include <assert.h>
+#include <stdint.h>
+
+#include <sys/mman.h>
+#include <sys/shm.h>
+#include <sys/wait.h>
+#include <sys/types.h>
+
+/* This is a somewhat ugly hack for the experimental 'trace-pc-guard' mode.
+   Basically, we need to make sure that the forkserver is initialized after
+   the LLVM-generated runtime initialization pass, not before. */
+
+#ifdef USE_TRACE_PC
+#define CONST_PRIO 5
+#else
+#define CONST_PRIO 0
+#endif                                                     /* ^USE_TRACE_PC */
+
+#include <sys/mman.h>
+#include <fcntl.h>
+
+/* Globals needed by the injected instrumentation. The __afl_area_initial region
+   is used for instrumentation output before __afl_map_shm() has a chance to
+   run. It will end up as .comm, so it shouldn't be too wasteful. */
+
+// In CmpLog, the only usage of __afl_area_ptr is to report errors
+u8* __afl_area_ptr;
+
+struct cmp_map* __afl_cmp_map;
+__thread u32    __afl_cmp_counter;
+
+/* Running in persistent mode? */
+
+static u8 is_persistent;
+
+/* SHM setup. */
+
+static void __afl_map_shm(void) {
+
+  u8* id_str = getenv(SHM_ENV_VAR);
+
+  /* If we're running under AFL, attach to the appropriate region, replacing the
+     early-stage __afl_area_initial region that is needed to allow some really
+     hacky .init code to work correctly in projects such as OpenSSL. */
+
+  if (id_str) {
+
+#ifdef USEMMAP
+    const char*    shm_file_path = id_str;
+    int            shm_fd = -1;
+    unsigned char* shm_base = NULL;
+
+    /* create the shared memory segment as if it was a file */
+    shm_fd = shm_open(shm_file_path, O_RDWR, 0600);
+    if (shm_fd == -1) {
+
+      printf("shm_open() failed\n");
+      exit(1);
+
+    }
+
+    /* map the shared memory segment to the address space of the process */
+    shm_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, shm_fd, 0);
+    if (shm_base == MAP_FAILED) {
+
+      close(shm_fd);
+      shm_fd = -1;
+
+      printf("mmap() failed\n");
+      exit(2);
+
+    }
+
+    __afl_area_ptr = shm_base;
+#else
+    u32 shm_id = atoi(id_str);
+
+    __afl_area_ptr = shmat(shm_id, NULL, 0);
+#endif
+
+    /* Whooooops. */
+
+    if (__afl_area_ptr == (void*)-1) _exit(1);
+
+    /* Write something into the bitmap so that even with low AFL_INST_RATIO,
+       our parent doesn't give up on us. */
+
+    __afl_area_ptr[0] = 1;
+
+  }
+
+  id_str = getenv(CMPLOG_SHM_ENV_VAR);
+
+  if (id_str) {
+
+    u32 shm_id = atoi(id_str);
+
+    __afl_cmp_map = shmat(shm_id, NULL, 0);
+
+    if (__afl_cmp_map == (void*)-1) _exit(1);
+
+  }
+
+}
+
+/* Fork server logic. */
+
+static void __afl_start_forkserver(void) {
+
+  static u8 tmp[4];
+  s32       child_pid;
+
+  u8 child_stopped = 0;
+
+  void (*old_sigchld_handler)(int) = 0;  // = signal(SIGCHLD, SIG_DFL);
+
+  /* Phone home and tell the parent that we're OK. If parent isn't there,
+     assume we're not running in forkserver mode and just execute program. */
+
+  if (write(FORKSRV_FD + 1, tmp, 4) != 4) return;
+
+  while (1) {
+
+    u32 was_killed;
+    int status;
+
+    /* Wait for parent by reading from the pipe. Abort if read fails. */
+
+    if (read(FORKSRV_FD, &was_killed, 4) != 4) _exit(1);
+
+    /* If we stopped the child in persistent mode, but there was a race
+       condition and afl-fuzz already issued SIGKILL, write off the old
+       process. */
+
+    if (child_stopped && was_killed) {
+
+      child_stopped = 0;
+      if (waitpid(child_pid, &status, 0) < 0) _exit(1);
+
+    }
+
+    if (!child_stopped) {
+
+      /* Once woken up, create a clone of our process. */
+
+      child_pid = fork();
+      if (child_pid < 0) _exit(1);
+
+      /* In child process: close fds, resume execution. */
+
+      if (!child_pid) {
+
+        signal(SIGCHLD, old_sigchld_handler);
+
+        close(FORKSRV_FD);
+        close(FORKSRV_FD + 1);
+        return;
+
+      }
+
+    } else {
+
+      /* Special handling for persistent mode: if the child is alive but
+         currently stopped, simply restart it with SIGCONT. */
+
+      kill(child_pid, SIGCONT);
+      child_stopped = 0;
+
+    }
+
+    /* In parent process: write PID to pipe, then wait for child. */
+
+    if (write(FORKSRV_FD + 1, &child_pid, 4) != 4) _exit(1);
+
+    if (waitpid(child_pid, &status, is_persistent ? WUNTRACED : 0) < 0)
+      _exit(1);
+
+    /* In persistent mode, the child stops itself with SIGSTOP to indicate
+       a successful run. In this case, we want to wake it up without forking
+       again. */
+
+    if (WIFSTOPPED(status)) child_stopped = 1;
+
+    /* Relay wait status to pipe, then loop back. */
+
+    if (write(FORKSRV_FD + 1, &status, 4) != 4) _exit(1);
+
+  }
+
+}
+
+/* A simplified persistent mode handler, used as explained in README.llvm. */
+
+int __afl_persistent_loop(unsigned int max_cnt) {
+
+  static u8  first_pass = 1;
+  static u32 cycle_cnt;
+
+  if (first_pass) {
+
+    /* Make sure that every iteration of __AFL_LOOP() starts with a clean slate.
+       On subsequent calls, the parent will take care of that, but on the first
+       iteration, it's our job to erase any trace of whatever happened
+       before the loop. */
+
+    if (is_persistent) {
+
+      // memset(__afl_area_ptr, 0, MAP_SIZE);
+      __afl_area_ptr[0] = 1;
+
+    }
+
+    cycle_cnt = max_cnt;
+    first_pass = 0;
+    return 1;
+
+  }
+
+  if (is_persistent) {
+
+    if (--cycle_cnt) {
+
+      raise(SIGSTOP);
+
+      __afl_area_ptr[0] = 1;
+
+      return 1;
+
+    } else {
+
+      /* When exiting __AFL_LOOP(), make sure that the subsequent code that
+         follows the loop is not traced. We do that by pivoting back to the
+         dummy output region. */
+
+      // __afl_area_ptr = __afl_area_initial;
+
+    }
+
+  }
+
+  return 0;
+
+}
+
+/* This one can be called from user code when deferred forkserver mode
+    is enabled. */
+
+void __afl_manual_init(void) {
+
+  static u8 init_done;
+
+  if (!init_done) {
+
+    __afl_map_shm();
+    __afl_start_forkserver();
+    init_done = 1;
+
+  }
+
+}
+
+/* Proper initialization routine. */
+
+__attribute__((constructor(CONST_PRIO))) void __afl_auto_init(void) {
+
+  is_persistent = !!getenv(PERSIST_ENV_VAR);
+
+  if (getenv(DEFER_ENV_VAR)) return;
+
+  __afl_manual_init();
+
+}
+
+///// CmpLog instrumentation
+
+void __sanitizer_cov_trace_cmp1(uint8_t Arg1, uint8_t Arg2) {
+
+  return;
+
+}
+
+void __sanitizer_cov_trace_cmp2(uint16_t Arg1, uint16_t Arg2) {
+
+  if (!__afl_cmp_map) return;
+
+  uintptr_t k = (uintptr_t)__builtin_return_address(0);
+  k = (k >> 4) ^ (k << 8);
+  k &= CMP_MAP_W - 1;
+
+  u32 hits = __afl_cmp_map->headers[k].hits;
+  __afl_cmp_map->headers[k].hits = hits + 1;
+  // if (!__afl_cmp_map->headers[k].cnt)
+  //  __afl_cmp_map->headers[k].cnt = __afl_cmp_counter++;
+
+  __afl_cmp_map->headers[k].shape = 1;
+  //__afl_cmp_map->headers[k].type = CMP_TYPE_INS;
+
+  hits &= CMP_MAP_H - 1;
+  __afl_cmp_map->log[k][hits].v0 = Arg1;
+  __afl_cmp_map->log[k][hits].v1 = Arg2;
+
+}
+
+void __sanitizer_cov_trace_cmp4(uint32_t Arg1, uint32_t Arg2) {
+
+  if (!__afl_cmp_map) return;
+
+  uintptr_t k = (uintptr_t)__builtin_return_address(0);
+  k = (k >> 4) ^ (k << 8);
+  k &= CMP_MAP_W - 1;
+
+  u32 hits = __afl_cmp_map->headers[k].hits;
+  __afl_cmp_map->headers[k].hits = hits + 1;
+
+  __afl_cmp_map->headers[k].shape = 3;
+
+  hits &= CMP_MAP_H - 1;
+  __afl_cmp_map->log[k][hits].v0 = Arg1;
+  __afl_cmp_map->log[k][hits].v1 = Arg2;
+
+}
+
+void __sanitizer_cov_trace_cmp8(uint64_t Arg1, uint64_t Arg2) {
+
+  if (!__afl_cmp_map) return;
+
+  uintptr_t k = (uintptr_t)__builtin_return_address(0);
+  k = (k >> 4) ^ (k << 8);
+  k &= CMP_MAP_W - 1;
+
+  u32 hits = __afl_cmp_map->headers[k].hits;
+  __afl_cmp_map->headers[k].hits = hits + 1;
+
+  __afl_cmp_map->headers[k].shape = 7;
+
+  hits &= CMP_MAP_H - 1;
+  __afl_cmp_map->log[k][hits].v0 = Arg1;
+  __afl_cmp_map->log[k][hits].v1 = Arg2;
+
+}
+
+#if defined(__APPLE__)
+#pragma weak __sanitizer_cov_trace_const_cmp1 = __sanitizer_cov_trace_cmp1
+#pragma weak __sanitizer_cov_trace_const_cmp2 = __sanitizer_cov_trace_cmp2
+#pragma weak __sanitizer_cov_trace_const_cmp4 = __sanitizer_cov_trace_cmp4
+#pragma weak __sanitizer_cov_trace_const_cmp8 = __sanitizer_cov_trace_cmp8
+#else
+void __sanitizer_cov_trace_const_cmp1(uint8_t Arg1, uint8_t Arg2)
+    __attribute__((alias("__sanitizer_cov_trace_cmp1")));
+void __sanitizer_cov_trace_const_cmp2(uint16_t Arg1, uint16_t Arg2)
+    __attribute__((alias("__sanitizer_cov_trace_cmp2")));
+void __sanitizer_cov_trace_const_cmp4(uint32_t Arg1, uint32_t Arg2)
+    __attribute__((alias("__sanitizer_cov_trace_cmp4")));
+void __sanitizer_cov_trace_const_cmp8(uint64_t Arg1, uint64_t Arg2)
+    __attribute__((alias("__sanitizer_cov_trace_cmp8")));
+#endif                                                /* defined(__APPLE__) */
+
+void __sanitizer_cov_trace_switch(uint64_t Val, uint64_t* Cases) {
+
+  for (uint64_t i = 0; i < Cases[0]; i++) {
+
+    uintptr_t k = (uintptr_t)__builtin_return_address(0) + i;
+    k = (k >> 4) ^ (k << 8);
+    k &= CMP_MAP_W - 1;
+
+    u32 hits = __afl_cmp_map->headers[k].hits;
+    __afl_cmp_map->headers[k].hits = hits + 1;
+
+    __afl_cmp_map->headers[k].shape = 7;
+
+    hits &= CMP_MAP_H - 1;
+    __afl_cmp_map->log[k][hits].v0 = Val;
+    __afl_cmp_map->log[k][hits].v1 = Cases[i + 2];
+
+  }
+
+}
+
+
+void __sanitizer_cov_trace_pc_guard(uint32_t* guard) {
+}
+
+void __sanitizer_cov_trace_pc_guard_init(uint32_t* start, uint32_t* stop) {
+}
+
+//// Library functions hooks
+
+// TODO